●Reliable Material The wheel axle reduction bushings are made of plastic, durable and sturdy. ●Dimensions: Reducing socket height 25mm, outer diameter 25mm, inner diameter 13mm ●Fitment: Replacement wheel reduction rings, fits for trolley, sack truck and trolley wheels, fits 1" inner diameter trolley tires. ●EASY INSTALLATION - Each reduction ring simply pushes into the hole of the trolley wheel. ●Package Included: 4pcs Wheel Axle Reduction Rings